Coupling of rare-earth ions (Pr$^{3+})$ in a crystal
(Y$_{2}$SiO$_{5})$ to a
macroscopic cavity mode was demonstrated by observing optical
bistability
and normal-mode peaks, which is sometimes described as vacuum Rabi
splitting, due to sweeping-laser-induced population
redistribution of the
ions. The experimentally evaluated coupling constant between the
individual
ions and the single cavity mode is 15 kHz, which is comparable
with or
larger than the dissipation of the ions. The coupling constant
will exceed
the cavity dissipation with a narrowing of the mode waist of the
cavity to
the wavelength. The results advance the application of a coupled
system of
rare-earth ions in a crystal and an optical cavity for quantum
information
processing.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.MAR.R1.236